ES2924683T3 - High-strength, corrosion-resistant 6xxx series aluminum alloys and methods for making the same - Google Patents

Abstract

The present disclosure generally provides 6xxx series aluminum alloys and methods of making them, such as casting and rolling. The description also provides products made from such alloys. The disclosure also provides for various end uses of such products, such as automotive, transportation, electronics, aerospace, and industrial applications, among others. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

High-strength, corrosion-resistant 6xxx series aluminum alloys and methods for making the same

Countryside

The present disclosure generally provides 6xxx series aluminum alloys. The disclosure also provides products made from such alloys and methods of making such products, such as by casting and rolling. The disclosure also provides various end uses for such products, such as in automotive, transportation, electronic, industrial, aerospace, and other applications.

Background

High strength aluminum alloys are desirable for use in many different applications, especially those where strength and durability are particularly desirable. For example, aluminum alloys with the 6xxx series designation are commonly used, instead of steel, for automotive structural and closure panel applications. Since aluminum alloys are generally about 2.8 times less dense than steel, the use of such materials reduces vehicle weight and substantially improves fuel economy. Still, the use of currently available aluminum alloys in automotive applications poses certain challenges.

A particular challenge is related to the tendency of 6xxx series aluminum alloys to be weaker than steel. In some cases, it is possible to alter the alloy composition to increase the strength of the finished aluminum alloy product, for example by increasing the amount of silicon or copper in the alloy composition. However, increasing the concentration of silicon or copper in the alloy often leads to the formation of grain boundary precipitates, which in turn reduces the corrosion resistance of the finished product. US 5,961,752 A discloses an aluminum alloy containing 0.2 to 2% by weight of Si, 0.3 to 1.7% by weight of Mg, 0.32 to 1.2% by weight of Cu, 0.05 to 0.4 wt.% Cr, 0.01 to 0.4 wt.% Fe, max. 0.2% by weight of Ti, less than 0.05% by weight of Zn and at least one of: 0.01 to 0.3% by weight of V, 0.001 to 0.1% by weight of weight of Be and 0.01 to 0.1% by weight of Sr. FR 2902442 A1 discloses an aluminum alloy containing 0.2 to 1.3% by weight of Si, 0.4 to 1 0.5 wt% Mg, 0.1 to 1.1 wt% Cu, up to 0.7 wt% Mn, 0.02 to 0.3 wt% Fe, up to 0 0.9 wt% Zn, up to 0.25 wt% Cr, 0.06 to 0.19 wt% Ti, up to 0.2 wt% Zr and up to 0.5 wt% by weight of Ag, where the sum of Ti and Cr is greater than 0.1 and less than 0.35% by weight. Document FR 2826979 A1 refers to an aluminum alloy product containing from 0.8 to 1.3 wt% Si, 0.2 to 0.45 wt% Cu, 0.5 to 1.1 wt% Mn, 0.45 to 1.0 wt% Mg , 0.01 to 0.3 wt% Fe, less than 0.25 wt% Zr, Cr, Ti and V and less than 0.35 wt% Zn.

Original equipment manufacturers (OEMs) continue to face pressure from regulators and consumers to offer more fuel-efficient vehicles that are also safe and durable.

Summary

The present disclosure provides novel 6xxx series aluminum alloys having high strength and high corrosion resistance. Among other things, the inclusion of higher amounts of minor alloying elements (eg, Mn, Cr, Zr, V, etc.) improves the corrosion resistance of products formed from the aluminum alloy without causing a loss of corrosion. substantial resistance. Without being bound by any particular theory, it is believed that the inclusion of larger amounts of minor alloying elements leads to the formation of a large number of dispersoids during homogenization, which can serve as nucleation sites for silicon or copper. Since these precipitates form at the location of the dispersoids, they do not form to any substantial degree at grain boundaries. Therefore, grain boundaries do not become sites for subsequent intergranular corrosion.

An aluminum alloy is disclosed comprising 0.4 to 0.7 weight percent Si; 0.4 to 1.6 weight percent Mg; 0.2 to 1.5 weight percent Cu; not more than 0.5 weight percent Fe; not more than 0.1 weight percent Cr; not more than 0.25 weight percent Mn; not more than 0.05 weight percent of V; 0.02 to 0.2 weight percent Zr; up to 0.1 weight percent Ti; not more than 0.2 percent by weight of Sn, not more than 0.2 percent by weight of Zn, not more than 0.2 percent by weight of Ni or not more than 0.2 percent by weight of Sc, with not more than 0.5 weight percent in total; and the balance aluminum in an amount of at least 95.0 weight percent. Throughout this application, all elements are described in weight percent (wt%) based on the total weight of the alloy. These alloys exhibit high strength and corrosion resistance and can be suitably used in a variety of applications, including automotive, transportation, electronic, aerospace, and industrial applications, among others.

An aluminum alloy product is also disclosed, comprising an aluminum alloy as described above. In some cases, the aluminum alloy product is an ingot, strip, plate, slab, billet, or other aluminum alloy product. In other examples, the aluminum alloy product is a rolled aluminum alloy product, which is formed by a process that includes rolling the aluminum alloy product, for example, to a desired thickness. The rolled aluminum alloy product may be an aluminum alloy sheet. Such plates may have any suitable temper ranging from, for example, T1 to T9 temper, and any suitable gauge. In other examples, the disclosure provides aluminum plates, extrusions, castings and forgings comprising a 6xxx series alloy, as provided herein.

Also disclosed is a method of making an aluminum alloy product, the method comprising providing an aluminum alloy, as described herein, wherein the aluminum alloy is provided in a molten state as a molten aluminum alloy, and continuously casting the molten aluminum alloy to form an aluminum alloy product. The method may further comprise rolling the aluminum alloy product, for example after homogenization, to form a rolled aluminum alloy product, such as an aluminum alloy sheet.

In other examples, the method may include direct quench (DC) casting of the molten aluminum alloy to form an aluminum alloy product, such as an ingot, and rolling of the aluminum alloy product. aluminum, for example, after homogenization, to form a rolled aluminum alloy product, such as an aluminum alloy sheet.

An article of manufacture comprising an aluminum alloy product, as described herein, is also disclosed. The article of manufacture may include a rolled aluminum alloy product. Examples of such articles of manufacture include, but are not limited to, an automobile, a truck, a trailer, a train, a railroad car, an aircraft, a body panel or part for any of the foregoing, a bridge, a conduit, a pipe, a tube, a boat, a ship, a storage container, a storage tank, a piece of furniture, a window, a door, a railing, a functional or decorative architectural piece, a pipe railing, a component electrical, conduit, beverage container, food container, or foil. In some examples, the articles of manufacture are automotive or transportation body parts, including motor vehicle body parts (for example, bumpers, side beams, roof beams, cross beams, pillar braces, interior panels, exterior panels, side panels, hood interiors, hood exteriors and trunk lid panels). The article of manufacture may also include electronic products, such as housings for electronic devices.

Additional aspects and embodiments are set forth in the detailed description, claims, non-limiting examples, and drawings, which are included herein.

Brief description of the drawings

FIG. 1 shows the yield strength and VDA angle of the bending capacity test for four alloys (A1-A4), each of which was prepared in tempers t4 and T6.

FIG. 2 shows optical micrographs (OM) for four alloys (A1-A4), each prepared in the T6 temper and subjected to intergranular corrosion (IGC) testing. ) set forth in ISO 11846B (1995) for 24 hours.

FIG. 3 shows the maximum and average pitting depths and the number of pits after the samples were subjected to the intergranular corrosion (IGC) test set forth in ISO 11846B (1995) for 24 hours. The four samples are the four alloys (A1-A4), each of which was prepared in the T6 temper.

FIG. 4 shows optical micrographs (OM) for a 6xxx series aluminum alloy to which Zr (A4) has been added, each in the T6 temper, but prepared in different ways and subjected to intergranular corrosion (IGC) testing. set forth in ISO 11846B (1995) for 24 hours. The four different preparation conditions are indicated in the figure and include (a) homogenization at a temperature increase of 50 °C/h up to a maximum of 450 °C without stabilization; (b) homogenization at a temperature increase of 50 °C/h up to a maximum of 500 °C without stabilization; (c) homogenization at a temperature increase of 50 °C/h up to a maximum of 540 °C without stabilization; and (d) homogenization at a temperature increase of 50 °C/h up to a maximum of 560 °C with a stabilization of 6 hours after homogenization.

FIG. 5 shows optical micrographs (OM) for a number of different 6xxx series aluminum alloys cast by different methods, including (a) alloy A1 cast by continuous casting (CC) using a double belt caster, (b) alloy A2 continuous cast using a double belt caster, (c) alloy A3 continuous cast using a double belt caster, (d) alloy A4 continuous cast using a double belt caster and (e) cast alloy A1 by casting direct cooling (DC), where the samples were prepared in the T6 tempering and subjected to the intergranular corrosion test (IGC) exposed in the ISO 11846B (1995) standard for 24 hours. Detailed description

The present disclosure provides novel 6xxx series aluminum alloys and methods for making and using such alloys. These alloys have high strength and resistance to corrosion. Surprisingly, these alloys include additional amounts of one or more minor alloying elements (eg, manganese, chromium, zirconium, vanadium, etc.) whose presence acts to reduce silicon and/or copper precipitation at grain boundaries. Therefore, the inclusion of these minor alloying elements results in high strength aluminum alloys containing copper and/or excess silicon without experiencing a decrease in corrosion resistance due to precipitation of these elements at the boundaries. grain.

Definitions and descriptions

The term "invention" and the expressions "the invention", "this invention", and "the present invention" used herein are intended to refer broadly to all subject matter of this patent application and the claims set forth below. It should be understood that statements contained in these terms and expressions do not limit the subject matter described herein or limit the meaning or scope of the patent claims set forth below.

In this description, reference is made to alloys identified by AA numbers and other related designations, such as "series" or "6xxx". To understand the most commonly used numerical naming system for naming and identifying aluminum and its alloys, see the document "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" or "Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot", both published by The Aluminum Association.

As used in this document, the meaning of "a", "an", and "the" includes singular and plural references, unless the context clearly dictates otherwise.

As used herein, a plate generally has a thickness greater than about 15mm. For example, a plate can refer to an aluminum product that is thicker than 15mm, thicker than 20mm, thicker than 25mm, thicker than 30mm, thicker than 35mm, thicker than 40mm, thicker than 45mm. mm, more than 50 mm or more than 100 mm.

As used herein, a sheet (also known as sheet metal) generally has a thickness of from about 4mm to about 15mm. For example, a sheet may have a thickness of 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.

As used herein, a sheet generally refers to an aluminum product having a thickness of less than about 4mm. For example, a sheet may have a thickness of less than 4 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.3 mm or less than 0.1 mm. .

In this application reference is made to the tempering or condition of the alloy. For descriptions of the most commonly used alloy tempers, see "American National Standards (ANSI) H35 on Alloy and Temper Designation Systems." A condition or temper F refers to an aluminum alloy as manufactured. A condition or temper O refers to an aluminum alloy after annealing. A T1 condition or temper refers to an aluminum alloy cooled from hot working and naturally aged (eg, at room temperature). A T2 condition or temper refers to an aluminum alloy quenched from hot work, cold worked and naturally aged. A T3 condition or temper refers to a naturally aged, cold worked, solution heat treated aluminum alloy. A condition or T4 temper refers to a naturally aged solution heat treated aluminum alloy. A T5 condition or temper refers to an aluminum alloy cooled from hot working and artificially aged (at elevated temperatures). A T6 condition or temper refers to an artificially aged solution heat treated aluminum alloy. A T7 condition or temper refers to an artificially overaged solution heat treated aluminum alloy. A T8 condition or temper refers to an artificially aged, cold worked, solution heat treated aluminum alloy. A condition or temper T9 refers to a solution heat treated, artificially aged and cold worked aluminum alloy.

As used herein, expressions such as "cast metal product", "cast product", "cast aluminum alloy product" and the like are interchangeable and refer to a product produced by direct chill casting (including direct chill co-casting) or semi-continuous casting, continuous casting (including, for example, by using a double-belt caster, a twin-roll caster, a block casting or any other continuous casting machine), electromagnetic casting, top hot casting or any other casting method.

As used herein, the meaning of "room temperature" can include a temperature from about 15°C to about 30°C, for example, from about 15°C, from about 16°C, from about 17°C, about 18°C, about 19°C, about 20°C, about 21°C, about 22°C, about 23°C, about 24°C, about 25°C, about 26 °C, about 27 °C, about 28 °C, about 29 °C or about 30 °C. All ranges disclosed herein are to be understood to encompass any and all subranges included therein. For example, a stated range of "1 to 10" should be considered to include any and all subranges between (and including) the minimum value of 1 and the maximum value of 10; that is, all subintervals that start with a minimum value of 1 or more, such as 1 to 6.1, and end with a maximum value of 10 or less, such as 5.5 to 10.

In the following examples, aluminum alloys are described in terms of their elemental composition in percent by weight (% by weight). In each alloy, the remainder is aluminum unless otherwise noted. In some examples, the alloys disclosed in this document have a maximum weight percent of 0.15% for the sum of all impurities.

Alloy composition

The alloys described herein are novel 6xxx series aluminum alloys. Aluminum alloys exhibit high yield strength and flexural strength, along with unexpectedly high corrosion resistance at grain boundaries. The properties of aluminum alloys are achieved through the compositions and/or methods for making the alloys.

In some examples, the aluminum alloy has the elemental composition set forth in Table 1.

Table 1

The alloy compositions described in this document include 0.4% to 0.7% silicon (Si). In some examples, the alloy compositions may include about 0.4%, about 0.5%, about 0.6%, or about 0.7%. All percentages are expressed in % by weight.

Alloy compositions described herein include 0.4% to 1.6% magnesium (Mg). For example, the alloy compositions may include Mg in an amount of from about 0.4% to about 1.2%, from about 0.4% to about 1.0%, from about 0.5% to about 1.2%, from about 0.5% to about 1.0%, or from about 0.4% to about 0.7% Mg. In some examples, the alloy compositions may include about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1.0%, about 1.1%, about 1.2%, about 1.3%, about 1.4% Mg or about 1.5% Mg. All percentages are expressed in % by weight.

Alloy compositions described herein include 0.2% to 1.5% copper (Cu). For example, the alloy compositions may include Cu in an amount of from about 0.3% to about 1.1%, from about 0.4% to about 1.0%, from about 0.4% to about 0.9%, from about 0.4% to about 0.8%, or from about 0.4% to about 0.7%. In some examples, the alloy compositions may include about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7 %, about 0.8%, about 0.9%, about 1.0%, about 1.1%, about 1.2% Cu, about 1.3% Cu, about 1.4% Cu or about 1.5% Cu. All percentages are expressed in % by weight.

The alloy compositions described in this document include up to 0.5% iron (Fe). For example, the alloy compositions may include Fe in an amount of from 0% to about 0.4%, from 0% to about 0.3%, from about 0.1% to about 0.5%, or from about 0.1% to about 0.3%. In some examples, the alloy compositions may include about 0.1%, about 0.2%, about 0.3%, about 0.4%, or about 0.5% Fe. In some cases , Fe is not present in the alloy (ie, it is 0%). All percentages are expressed in % by weight.

The alloy compositions described herein include up to 0.1% titanium (Ti). For example, the alloy compositions may include Ti in an amount of from 0% to about 0.07%, from 0% to about 0.05%, from about 0.01% to about 0.1%, from about 0.01% to about 0.07% or from about 0.01% to about 0.05%. In some examples, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06 %, about 0.07%, about 0.08%, about 0.09%, or about 0.10%. In some cases Ti is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

Alloy compositions include 0 to 0.1% Cr. In some examples, alloy compositions may include Cr in an amount of 0% to about 0.07%, 0% to about 0.05% , from about 0.01% to about 0.1%, from about 0.01% to about 0.07%, or from about 0.01 to about 0.05%. In some such cases, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, or about 0.10% Cr. In some cases, Cr is not present in the alloy (i.e., is 0%). All percentages are expressed in % by weight.

In some examples disclosed in this document, such as those set forth in Table 1, the alloy composition has an excess of zirconium (Zr) above what may be typical for a 6xxx series aluminum alloy. Alloy compositions include 0.02% to 0.2% Zr. In some examples, the alloy compositions may include Zr in an amount of from about 0.04% to about 0.18%, from about 0.06% to about 0.16%, from about 0.07 % to about 0.16% or from about 0.08% to about 0.16%. In some such cases, the alloy compositions may include about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.06% 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0.13%, about 0, 14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.20% Zr. All percentages are expressed in % by weight.

The alloy compositions comprise 0% to 0.25% Mn. In some examples, the alloy compositions may include Mn in an amount of from 0% to about 0.23%, from 0% to about 0.21%, from about 0.05% to about 0.23% , from about 0.05% to about 0.21% or from about 0.10% to about 0.23%. In some such cases, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0, 13%, approximately 0.14%, approximately 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, about 0.20%, about 0.21%, about 0.22%, about 0.23%, about 0.24%, or about 0.25% Mn. In some cases, the Mn is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

The alloy compositions comprise from 0% to 0.05% V. In some examples, the alloy compositions may include V in an amount from 0% to about 0.02% or from about 0.01% to about 0.02%. In some such cases, the alloy compositions may include about 0.01% or about 0.02%. In some cases V is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

Optionally, the alloy compositions disclosed herein may have minor amounts of other elements, including scandium (Sc), tin (Sn), zinc (Zn), and nickel (Ni).

In some examples, the alloy compositions may include Sc in an amount of from 0% to 0.20%, from 0% to about 0.15%, or from 0% to about 0.10%. In some such examples, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0, 13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.20 % Sc. In some cases, Sc is not present in the alloy (ie, it is 0%). All percentages are expressed in % by weight.

In some examples, the alloy compositions may include Sn in an amount of from 0% to 0.20%, from 0% to about 0.15%, or from 0% to about 0.10%. In some such examples, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0, 13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.20 %Sn. In some cases, Sn is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

In some examples, the alloy compositions may include Zn in an amount of from 0% to 0.20%, from 0% to about 0.15%, or from 0% to about 0.10%. In some such examples, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0, 13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.20 % Zn. In some cases Zn is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

In some examples, the alloy compositions may include Ni in an amount of from 0% to 0.20%, from 0% to about 0.15%, or from 0% to about 0.10%. In some such examples, the alloy compositions may include about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.05% 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.10%, about 0.11%, about 0.12%, about 0, 13%, about 0.14%, about 0.15%, about 0.16%, about 0.17%, about 0.18%, about 0.19%, or about 0.20 % Ni. In some cases Ni is not present in the alloy (ie it is 0%). All percentages are expressed in % by weight.

Optionally, the alloy compositions disclosed in this document, including those set forth in Table 1, may also include other minor elements, sometimes referred to as impurities, in amounts of 0.05% or less, of the 0.04% or less, 0.03% or less, 0.02% or less, or 0.01% or less. These impurities may include, but are not limited to, Ga, Ca, Bi, Na, Pb, or combinations thereof. Therefore, Ga, Ca, Bi, Na or Pb may be present in the alloys in amounts of 0.05% or less, 0.04% or less, 0.03% or less, 0.02% or less or 0.01% or less. The sum of all impurities does not exceed 0.15 % (eg 0.10%). All percentages are expressed in % by weight.

The alloy compositions disclosed in this document have aluminum (Al) as the main component, usually in an amount of at least 95.0%. In some examples, the alloy compositions are at least 95.5%, at least 96.0%, at least 96.5%, at least 97.0%, or at least 97.5% Al .

Methods for preparing aluminum alloy products

In certain aspects, the disclosed alloy compositions are a product of a disclosed method. Without intending to limit the invention, the properties of the aluminum alloy are partially determined by the formation of microstructures during the preparation of the alloy.

The alloys described herein can be cast using a casting method known to those skilled in the art. For example, the casting process may include a direct chill (DC) casting process. Optionally, DC cast aluminum alloy products (eg ingots) can be surface flaked prior to further processing. Optionally, the casting process may include a continuous casting (CC) process. The cast aluminum alloy products may then be subjected to additional processing steps. In a non-limiting example, the processing method includes homogenization, hot rolling, solution heat treatment, and quenching. In some cases, the processing steps further include annealing and/or cold rolling, if desired. Homogenization

The homogenization step may include heating an aluminum alloy product prepared from an alloy composition described herein to a maximum metal temperature (PMT) of at least about 450°C. (eg, at least about 450°C, at least about 460°C, at least about 470°C, at least about 480°C, at least about 490°C, at least about 500°C, at least about 510 °C, at least about 520 °C, at least about 530 °C, at least about 540 °C, at least about 550 °C, at least about 560 °C, at least about 570 °C, or at least about 580 °C C). For example, the aluminum alloy product can be heated to a temperature of from about 520°C to about 580°C, from about 530°C to about 575°C, from about 535°C to about 570°C, from about 540°C to about 565°C, from about 545°C to about 560°C, from about 530°C to about 560°C, or from about 550°C to about 580°C. In some cases, the heating rate to PMT may be approximately 100°C/hour or less, 75°C/hour or less, 50°C/hour or less, 40°C/hour or less, 30°C /hour or less, 25°C/hour or less, 20°C/hour or less, or 15°C/hour or less. In other cases, the rate of heating to PMT may be from about 10°C/min to about 100°C/min (eg, from about 10°C/min to about 90°C/min, from about 10°C/min to about 90°C/min, from about 10°C/min to about 100°C/min). C/min to about 70°C/min, from about 10°C/min to about 60°C/min, from about 20°C/min to about 90°C/min, from about 30°C/min to about 80 °C/min, from about 40 °C/min to about 70 °C/min, or from about 50 °C/min to about 60 °C/min).

The aluminum alloy product is allowed to stabilize (ie, hold at the indicated temperature) for a period of time. According to one non-limiting example, the aluminum alloy product is allowed to settle for up to about 6 hours (eg, from about 30 minutes to about 6 hours, inclusive). For example, the aluminum alloy product can be stabilized at a temperature of at least 500°C for 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, or 6 hours, or anywhere in between.

hot rolling

After the homogenization step, a hot rolling step can be performed. In certain cases, aluminum alloy products are hot deposited and rolled with an inlet temperature range of approximately 500°C - 540°C. The inlet temperature can be, for example, approximately 505°C, 510°C, 515°C, 520°C, 525°C, 530°C, 535°C or 540°C. In certain cases, the hot rolling outlet temperature may vary from about 250°C to 380°C (eg, from about 330°C to 370°C). For example, hot rolling outlet temperature can be about 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C. C, 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, 355°C , 360 °C, 365 °C, 370 °C, 375 °C or 380 °C.

In certain cases, homogenized samples were immersion cooled from 560°C to 350°C (eg, to below recrystallization temperature) using a room temperature water spray. The samples were then hot rolled at a hot rolling inlet temperature of 340°C to 360°C to suppress precipitation of solute elements (eg Mg, Si, Cu, etc.). The relatively low hot rolling temperature helped keep the sheet from recrystallizing and maximized the stored energy of the rolling process. The finishing hot rolling temperature was between 270°C and 310°C. Immediately after hot rolling, the samples were immediately water quenched without any delay in exiting the hot rolling, with room temperature water. Immediate quenching with room temperature water was performed to avoid precipitation at the grain boundaries of the samples and to maximize the amount of solute elements in the solid solution that would precipitate out as a strengthening phase during artificial aging.

In certain examples, the aluminum alloy product is hot rolled to a gauge of about 4 mm to about 15 mm thick (for example, a gauge of about 5 mm to about 12 mm thick), which is known as iron. For example, the aluminum alloy product can be hot rolled to about 15mm thick gauge, about 14mm thick gauge, about 13mm thick gauge, about 12mm thick gauge , a gauge of approximately 11 mm thick, a gauge of approximately 10 mm thick, a gauge of approximately 9 mm thick, a gauge of approximately 8 mm thick, a gauge of approximately 7 mm thick, a gauge of approximately 6mm thick or about 5mm thick gauge.

In other examples, the aluminum alloy product may be hot rolled to a gauge greater than 15 mm thick (ie, a plate). For example, the aluminum alloy product can be hot rolled to about 25mm thick gauge, about 24mm thick gauge, about 23mm thick gauge, about 22mm thick gauge , a gauge about 21 mm thick, a gauge about 20 mm thick, a gauge about 19 mm thick, a gauge about 18 mm thick, a gauge about 17 mm thick, or a gauge about 16mm thick.

In other cases, the aluminum alloy product may be hot rolled to less than 4mm gauge (ie, a sheet). In some examples, the aluminum alloy product is hot rolled to a gauge of from about 1 mm to about 4 mm thick. For example, the aluminum alloy product can be hot rolled to about 4mm thick gauge, about 3mm thick gauge, about 2mm thick gauge, or about 1mm thick gauge. . Tempering plates, sheets and plates as rolled is known as F-tempering.

Optional processing steps: annealing step and cold rolling step

In certain aspects, the alloy is subjected to additional processing steps after the hot rolling step and before any subsequent steps (eg, before a solution heat treatment step). Additional processing steps may include an annealing process and a cold rolling step.

The annealing step can result in an alloy with texture-enhanced components (eg, an enhanced T4 alloy) with reduced anisotropy during forming operations, such as stamping, drawing, or bending. By applying the annealing step, the texture in the modified temper is controlled/designed to be more random and texture components (TC) that can produce strong formability anisotropy (e.g., Goss, Goss-ND or Cube-RD). This improved texture can potentially reduce bending anisotropy and can improve formability in forming when it comes to a circumferential drawing or stamping process, as it acts to reduce the variability of properties in different directions.

The annealing step may include heating the alloy from room temperature to a temperature of from about 400°C to about 500°C (eg, from about 405°C to about 495°C, from about 410°C to about 490°C). °C, from about 415 °C to about 485 °C, from about 420 °C to about 480 °C, from about 425 °C to about 475 °C, from about 430 °C to about 470 °C, from about 435 °C to about 465 °C from about 440 °C to about 460 °C, from about 445 °C to about 455 °C, from about 450 °C to about 460 °C, from about 400 °C to about 450 °C , from about 425 °C to about 475 °C or from about 450 °C to about 500 °C).

The aluminum alloy product (eg plate, sheet or sheet) can be stabilized at that temperature for a period of time. In a non-limiting example, the aluminum alloy is allowed to set for up to about 2 hours (eg, from about 15 to about 120 minutes, inclusive). For example, the aluminum alloy product can be stabilized at the temperature of about 400°C to about 500°C for 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, or 120 minutes, or anywhere in between.

In certain aspects, the alloy is not subjected to an annealing step.

Optionally, a cold rolling step may be applied to the alloy prior to the solution heat treatment step. In some examples, the rolled product from the hot rolling step (for example, the plate, sheet, or sheet) may be cold rolled to a thin gauge sheet (for example, about 4.0 to 4.5 mm ). In other examples, the rolled product is cold rolled to about 4.5mm, about 4.4mm, about 4.3mm, about 4.2mm, about 4.1mm, or about 4.0mm. In other examples, the rolled product is rolled to about 3.9mm, about 3.8mm, about 3.7mm, about 3.6mm, about 3.5mm, about 3.4mm, about 3.3mm, about 3 .2mm, about 3.1mm, about 3.0mm, about 2.9mm, about 2.8mm, about 2.7mm, about 2.6mm, about 2.5mm, about 2.4mm, about 2.3mm, about 2.2mm, about 2.1mm, about 2.0mm, about 1.9mm, about 1.8mm, about 1.7mm, about 1.6mm, about 1.5mm, about 1.4mm, about 1.3mm, about 1.2mm, about 1.1mm, or about 1.0mm.

Solution heat treatment

The solutionizing heat treatment step may include heating the aluminum alloy product from room temperature to a temperature of from about 520°C to about 590°C (eg, from about 520°C to about 580°C, from about 530 °C to about 570 °C, from about 545 °C to about 575 °C, from about 550 °C to about 570 °C, from about 555 °C to about 565 °C, from about 540 °C to about 560 °C, from about 560 °C to about 580 °C or from about 550 °C to about 575 °C). The aluminum alloy product can be stabilized at that temperature for a period of time. In certain aspects, the aluminum alloy product is allowed to settle for up to about 2 hours (eg, from about 10 seconds to about 120 minutes, inclusive). For example, the aluminum alloy product can be temperature stabilized from about 525°C to about 590°C for 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, 105 seconds, 110 seconds, 115 seconds, 120 seconds, 125 seconds, 130 seconds, 135 seconds, 140 seconds , 145 seconds or 150 seconds, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes, 90 minutes, 95 minutes, 100 minutes, 105 minutes, 110 minutes, 115 minutes, or 120 minutes, or anywhere in between.

In certain aspects, the solution heat treatment is carried out immediately after the hot or cold rolling step. In certain aspects, the solution heat treatment is performed after an annealing step.

Temper

In certain aspects, the aluminum alloy product may then be cooled to a temperature of about 25°C at a quenching rate that may vary between about 50°C/s and 400°C/s in a quenching step. depending on the caliber selected. For example, the quench rate can be from about 50°C/s to about 375°C/s, from about 60°C/s to about 375°C/s, from about 70°C/s to about 350°C/s. , from about 80 °C/s to about 325 °C/s, from about 90 °C/s to about 300 °C/s, from about 100 °C/s to about 275 °C/s, from about 125 °C/s to about 250 °C/s, about 150 °C/s to about 225 °C/s, or about 175 °C/s to about 200 °C/s.

In the quenching step, the aluminum alloy product is rapidly quenched with a liquid (eg, water) and/or a gas or other selected quenching medium. In certain respects, the aluminum alloy product can be quickly quenched with water. In certain aspects, the aluminum alloy product is air quenched.

Aging

The aluminum alloy product can be naturally aged over a period of time to result in T4 tempering. In certain aspects, the aluminum alloy product in the T4 temper can be artificially aged (AA) at between about 180°C and 225°C (for example, 185°C, 190°C, 195°C). °C, 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, or 225 °C) for a period of time to result in T6 tempering. Optionally, the aluminum alloy product may be cold worked and artificially aged for a period of from about 15 minutes to about 8 hours (for example, 15 minutes, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, or 8 hours, or anywhere in between) to result in the T8 temper.

coil production

The annealing step during production can also be applied to produce the aluminum alloy product in coil form to improve productivity or formability. For example, an aluminum alloy product in coil form can be supplied in the O temper, using a hot or cold rolling step and an annealing step, after the hot or cold rolling step. Forming can occur in O tempering, which is followed by solution heat treatment, quenching, and artificial aging/baking of the paint.

In certain aspects, to produce an aluminum alloy product in coil form and with high formability compared to F-tempering, an annealing step, as described herein, may be applied to the coil. Without intending to limit the invention, the purpose of annealing and annealing parameters may include (1) release work hardening in the material to gain formability; (2) recrystallize or recover the material without causing significant grain growth; (3) design or convert the texture to be appropriate for forming and for anisotropy reduction during formability; and (4) prevent coarsening of pre-existing precipitation particles.

Aluminum products and their properties

In some non-limiting examples, aluminum alloy products including the aluminum alloys disclosed herein have high yield strength and flexural strength and excellent corrosion resistance compared to conventional 6xxx series alloys.

In some examples, an aluminum alloy sheet prepared from the alloys disclosed herein has a tensile yield strength of at least about 265 MPa, when the sheet is in the T6 temper, and the tensile yield strength is measured in accordance with ASTM Test No. B557 (2015) with 2" GL. For example, the yield strength may be at least about 275 MPa or at least about 280 MPa. In some In other examples, the yield strength varies from about 265 MPa to about 400 MPa, from about 270 MPa to about 375 MPa, or from about 275 MPa to about 350 MPa.

An aluminum alloy sheet prepared from the alloys disclosed herein may have a bending angle of at least 55°, where the aluminum alloy sheet is in the T6 temper and the bending angle is measured according to the test set forth in VDA (German Verband der Automobilindustrie) Test No. 238-100, with the exception that the test was performed without pretensioning. In some cases, the aluminum alloy sheet has a bending angle of at least 56°, at least 57°, at least 58°, at least 59°, at least 60°, at least 61°, or at least 62° . In some other examples, the aluminum alloy sheet has a bending angle ranging from 55° to 75°, 57° to 72°, or 60° to 70°.

Aluminum alloy sheets prepared from the alloys disclosed herein have a corrosion resistance that provides an average depth of intergranular corrosion (IGC) attack of no greater than about 145 pm, when measured using the IGC test. ISO 11846B (1995) with a 24-hour exposure. In some additional examples, aluminum alloy sheets comprising the alloys disclosed herein have a corrosion resistance that provides an average depth of intergranular corrosion (IGC) attack of not more than 140 pm, not more than 135 pm, no later than 130 pm, no later than 125 pm, no later than 120 pm, no later than 115 pm, no later than 110 pm, no later than 105 pm, no later than 100 pm, no later than 95 pm, no later no later than 90 pm, no later than 85 pm, no later than 80 pm, no later than 75 pm, no later than 70 pm, no later than 65 pm, no later than 60 pm, no later than 55 pm, no later than 50 pm, no later than 45 pm, no later than 40 pm, no later than 35 pm, no later than 30 pm or no later than 25 pm.

In some examples, aluminum alloy sheets prepared from the alloys disclosed herein have a corrosion resistance that provides a maximum depth of intergranular corrosion (IGC) attack of no greater than about 215 μm, when measured using the ISO 11846B (1995) test with a 24 hour exposure. In some additional examples, the aluminum alloy sheets comprising the alloys disclosed in this document have a corrosion resistance that provides a maximum depth of intergranular corrosion (IGC) attack of not more than 210 jm, not more than 205 jm, not more than 200 jm, not more than 195 jm, not more than 190 jm, not more than 185 jm, not more than 180 jm, not more than 175 jm, not more than 170 jm, not more than 165 jm, not more 160 jm, not more than 155 jm, not more than 150 jm, not more than 145 jm, not more than 140 jm, not more than 135 jm, not more than 130 jm, not more than 125 jm, not more than 120 jm, not more than 115 jm, not more than 110 jm, not more than 105 jm, not more than 100 jm, not more than 95 jm, not more than 90 jm, not more than 85 jm, not more than 80 jm, not more than 75 jm, not more than 70 jm, not more than 65 jm, not more than 60 jm, not more than 55 jm, not more than 50 jm, not more than 45 jm, not more than 40 jm, not more of 35 jm, not more than 30 jm or not more than 25 jm.

In some additional examples, aluminum alloy sheets prepared from the alloys disclosed herein have a corrosion resistance that provides a maximum depth of intergranular corrosion (IGC) attack no greater than the average grain size of the alloys. grains of the surface tested, where pitting depth is measured using the ISO 11846B (1995) test with 24-hour exposure and the average grain size is calculated by measuring it using the ASTM E112 (2004) method . In some additional examples, the aluminum alloy sheets comprising the alloys disclosed in this document have a corrosion resistance that provides a maximum depth of intergranular corrosion (IGC) attack of no greater than 0.9 times the average grain size. , not more than 0.8 times the average grain size, not more than 0.7 times the average grain size, not more than 0.6 times the average grain size or not more than 0.5 times the average grain size grain.

In some additional examples, aluminum alloy sheets prepared from the alloys disclosed herein have a corrosion resistance that provides an average depth of intergranular corrosion (IGC) attack no greater than the average grain size of the alloys. grains of the surface tested, where pitting depth is measured using the ISO 11846B (1995) test with 24-hour exposure and the average grain size is calculated by measuring it using the ASTM E112 (2004) method . In some additional examples, the aluminum alloy sheets comprising the alloys disclosed in this document have a corrosion resistance that provides an average depth of intergranular corrosion (IGC) attack of no greater than 0.9 times the average grain size. , not more than 0.8 times the average grain size, not more than 0.7 times the average grain size, not more than 0.6 times the average grain size or not more than 0.5 times the average grain size grain.

The mechanical properties of aluminum alloy products can be controlled by various aging conditions depending on the intended use. As an example, aluminum alloy products can be produced (or supplied) in the T4 temper, the T6 temper, or the T8 temper. T4 plates, sheets or veneers can be provided, which refers to naturally aged solution heat treated plates, sheets or veneers. Optionally, these T4 sheets, plates and sheets may be subjected as received to one or more additional aging treatments to satisfy strength requirements. For example, plates, sheets and plates can be supplied in other tempers, such as T6 temper or T8 temper, by subjecting the T4 alloy material to the appropriate aging treatment, as described herein or as otherwise known. so experts in the field.

As disclosed in more detail above, the aluminum alloy products described herein in the form of plates, extrusions, castings and forgings, or other suitable products can be manufactured using techniques known to those skilled in the art. For example, plates including the aluminum alloys described herein can be prepared by processing an aluminum alloy product in a homogenization step. followed by a hot rolling stage. In the hot rolling step, the aluminum alloy product can be hot rolled to a gauge of 200mm thickness or less (for example, from 1mm to 200mm).

manufacturing items

The disclosure provides an article of manufacture including an aluminum alloy product disclosed herein. In some examples, the article of manufacture comprises a rolled aluminum alloy product. Examples of such articles of manufacture include, but are not limited to, an automobile, a truck, a trailer, a train, a railroad car, an aircraft, a body panel or part for any of the foregoing, a bridge, a conduit, a pipe, a tube, a boat, a ship, a storage container, a storage tank, a piece of furniture, a window, a door, a railing, a functional or decorative piece of architecture, a pipe railing, an electrical component, a conduit, a beverage container, a food container, or a sheet.

The aluminum alloy products disclosed herein may be used in automotive and/or transportation applications, including motor vehicle, aircraft, and railway applications, or in any other desired application. In some examples, the aluminum alloy products disclosed herein can be used to prepare motor vehicle body part products, such as bumpers, side beams, roof beams, cross beams, pillar reinforcements (for example, A-pillars, B-pillars, and C-pillars), interior panels, exterior panels, side panels, hood interiors, hood exteriors, or trunk lid panels. The aluminum alloys and methods described herein can also be used in aircraft or rail vehicle applications, to prepare, for example, external and internal panels.

The aluminum alloy products disclosed in this document can also be used in electronic applications. For example, the aluminum alloy products disclosed in this document can be used to prepare housings for electronic devices, including mobile phones and tablets. In some examples, the alloys can be used to prepare casings for the outer shell of mobile phones (eg smartphones) and the bottom shell of tablets.

The aluminum alloy products disclosed in this document can also be used in industrial applications. For example, the aluminum alloy products disclosed in this document can be used to prepare products for the general distribution market.

The following examples serve to further illustrate certain embodiments of the present disclosure without, at the same time, however, constituting any limitation thereof. On the contrary, it is to be clearly understood that various embodiments, modifications and equivalents thereof may be resorted to which, after reading the description of this document, may suggest themselves to those skilled in the art without departing from the spirit of the disclosure.

EXAMPLE 1 - Alloy Compositions

Five aluminum alloys (A1/alloy 1 (comparative), A2/alloy 2 (comparative), A3/alloy 3 (comparative), A4/alloy 4 and A5/alloy 5 (comparative)) were prepared, whose elemental compositions are shown in Table 2 below. Alloys A1, A2, A3, A4 and A5 were prepared according to the methods described herein. Elemental compositions are given in percentages by weight.

Table 2

EXAMPLE 2 - Resistance and bending capacity tests

Alloys A1-A4 (Table 2) were continuously cast, homogenized at 560 °C for 6 hours and then rolled to a thickness of 2 mm, each being prepared according to a T4 temper and a T4 temper. T6. FIG. 1 shows the results of the yield strength and bending capacity tests. The graph shows the results of yield strength tests in accordance with ASTM Test No. B557 (2015) with 5.08 cm (2") GL for T4 and T6 tempers for each alloy, which are plotted against the x-axis The graph also shows the angle for VDA Flex Test #238-100 (with the exception that the test was done without prestress), which is plotted against the y-axis.

EXAMPLE 3 - Intergranular Corrosion Test

Aluminum alloy sheets of alloys A1-A4 (Table 2) were prepared as described above in Example 2 in the T6 temper. FIG. 2 shows optical micrographs of the four samples after being subjected to the corrosion test set forth in ISO 11846B (1995), with an exposure time of 24 hours. FIG. 3 shows the results of pitting depth measurements on the treated samples, where, for each sample, the maximum and average pitting depth (in |jm) of pits having a depth of more than 10 jm is indicated. The diamond indicates the number of pits that are more than 10 jm deep within the test surface.

EXAMPLE 4 - Effect of homogenization

An aluminum alloy sheet of alloy A4 was prepared as described above in Example 2 in the T6 temper, except for differences in the pre-roll treatment of the sample. Four different preparation conditions were used, as indicated in FIG. 4: (a) homogenization with a temperature increase of 50 °C/h to a maximum of 450 °C without stabilization; (b) homogenization with a temperature increase of 50 °C/h to a maximum of 500 °C without stabilization; (c) homogenization with a temperature increase of 50 °C/h to a maximum of 540 °C without stabilization; and (d) homogenization with a temperature increase of 50 °C/h to a maximum of 560 °C with a stabilization of 6 hours after homogenization. FIG. 4 shows optical micrographs of the four samples after being subjected to the corrosion test set forth in ISO 11846B (1995), with an exposure time of 24 hours.

The amount of corrosion decreased as the homogenization time and temperature increased. For the sample prepared under condition (d), almost no corrosion pitting was observed after 24 hours of exposure in a corrosive environment. The longer homogenization was used to precipitate Zr dispersoids that would fix the grain boundary to result in a low angle grain boundary (low energy, less grain boundary precipitation) and act as heterogeneous precipitation sites that reduce/ remove precipitation at the grain boundary. The precipitation-free grain boundaries resulted in corrosion potentials similar to those of the grain nuclei and provided superior corrosion resistance compared to the other samples.

EXAMPLE 5 - Effect of casting method

Aluminum alloy sheets of alloys A1-A4 were prepared as described above in Example 2 and subjected to homogenization at 560°C, followed by aging for 6 hours, except for differences in the casting method. The samples were prepared in the T6 temper. Different casting methods were used for the different samples, as indicated in FIG. 5: (a) a standard 6xxx series aluminum alloy (A1) cast by continuous casting using a double belt caster ("A1_CC"); (b) A2 cast by continuous caster using a double belt caster ("A2_CC"); (c) A3 cast by continuous caster using a double belt caster ("A3_CC"); (d) A4 cast by continuous casting using a double belt caster ("A4_CC") and (e) A1 cast by direct chill casting (" ^A1_d C"). FIG. 5 shows optical micrographs of the five samples after being subjected to the corrosion test set forth in ISO 11846B (1995), with an exposure time of 24 hours.

The A4_CC sample showed almost no corrosion pitting compared to the other samples (A1_CC, A2_CC, A3_CC and A1_DC). Samples A1_CC and A1_DC, which had similar compositions, showed different corrosion morphologies due to their different casting and processing methods. The CC process route allowed most of the solute in solid solution to be evenly distributed compared to the DC process route, where the process resulted in microsegregation from the grain boundary to the grain core which deteriorated the performance/corrosion resistance. Reducing Cu content (A2_CC) also improved corrosion resistance compared to A1_CC, as it reduced total strengthening precipitates which reduced the overall driving force. The reduction of the Si content (A3_CC) also improved the corrosion resistance compared to A1_CC for the same reason. However, Si has a higher diffusivity compared to Cu and therefore the low Si version (A3_CC) showed more corrosion resistance compared to the low Cu version (A2_CC). Finally, the Zr-containing version (A4_CC) showed superior corrosion resistance/performance compared to A1_CC, A2_CC and A3_CC due to higher number density of Zr dispersoids that formed low angle grain boundaries (low energy, less precipitation) and acted as heterogeneous nucleation sites to prevent grain boundary precipitation and improve corrosion resistance.

Illustrations of suitable alloys, products and methods

As used below, any reference to a series of illustrative alloys, products, or methods is to be understood as referring to each of those alloys, products, or methods disjunctively (for example, "Figures 1-4" refer to are to be understood as "Illustration 1, 2, 3 or 4").

Illustration 1 is an aluminum alloy comprising: 0.4 to 0.7 weight percent Si; (b) 0.4 to 1.6 weight percent Mg; (c) 0.2 to 1.5 weight percent Cu; (d) not more than 0.5 weight percent Fe; (e) not more than 0.1 weight percent Cr; (f) not more than 0.25 weight percent Mn; (g) not more than 0.05 weight percent of V; (h) 0.02 to 0.2 weight percent Zr; (i) up to 0.1 percent by weight of You; (j) not more than 0.2 weight percent Sn, not more than 0.2 weight percent Zn, not more than 0.2 weight percent Ni, and not more than 0.2 weight percent by weight of Sc, with not more than 0.5 weight percent total; and (k) impurities in amounts of 0.05 weight percent or less, where the sum of all impurities does not exceed 0.15 weight percent, with the remainder being aluminum in an amount of at least 95 .0 percent by weight.

Illustration 2 is an alloy product comprising the aluminum alloy of any previous or subsequent illustration.

Illustration 3 is an alloy product of any illustration 2, wherein the aluminum alloy product is a rolled aluminum alloy product comprising a rolled surface.

Fig. 4 is an alloy product of any of Figs. 2-3, wherein the aluminum alloy product is an aluminum alloy sheet having a thickness of not more than 7 mm.

Figure 5 is an alloy product of Figure 4, where, when subjected to the test conditions set forth in ISO 11846B (1995) over a 24-hour exposure period, the rolled surface has a pitting depth maximum no greater than 140 pm.

Figure 6 is an alloy product of any of Figures 4-5, where the rolled surface has a maximum pit depth no greater than its average grain size, where the average grain size is measured by the method of ASTM E112 (2004).

Figure 7 is an alloy product of any of Figures 4-6, which, when rolled to a thickness of 2 mm and prepared with a T6 temper, has a yield strength of at least 260 MPa, when measured from according to ASTM Test No. B557 (2015), and a bending angle of at least 55°, when measured according to Test No. 238-100 of the German Association of the Automotive Industry ( VDA), with the exception that the test was performed without prestressing.

Illustration 8 is a method of making an aluminum alloy product, comprising: providing an aluminum alloy of illustration 1, wherein the aluminum alloy is provided in a molten state as a molten aluminum alloy; and continuously casting or chill casting the molten aluminum alloy to form an aluminum alloy product.

Figure 9 is a method of Figure 8, further comprising homogenizing the aluminum alloy product to form a homogenized aluminum alloy product, wherein the homogenization is carried out at a maximum temperature of at least 540° c.

Figure 10 is a method of Figure 8, further comprising hot rolling the homogenized aluminum alloy product to form an aluminum alloy sheet having a first thickness of not more than 7 mm.

Figure 11 is a method of any of Figures 8-10, where the aluminum alloy product is formed without using cold rolling.

EXAMPLE 4 - Effect of homogenization

An aluminum alloy sheet of alloy A4 was prepared as described above in Example 2 in the T6 temper, except for differences in the pre-roll treatment of the sample. Four different preparation conditions were used, as indicated in FIG. 4: (a) homogenization with a temperature increase of 50 °C/h to a maximum of 450 °C without stabilization; (b) homogenization with a temperature increase of 50 °C/h to a maximum of 500 °C without stabilization; (c) homogenization with a temperature increase of 50 °C/h to a maximum of 540 °C without stabilization; and (d) homogenization with a temperature increase of 50 °C/h to a maximum of 560 °C with a stabilization of 6 hours after homogenization. FIG. 4 shows optical micrographs of the four samples after being subjected to the corrosion test set forth in ISO 11846B (1995), with an exposure time of 24 hours.

The amount of corrosion decreased as the homogenization time and temperature increased. For the sample prepared under condition (d), almost no corrosion pitting was observed after 24 hours of exposure in a corrosive environment. The longer homogenization was used to precipitate Zr dispersoids that would fix the grain boundary to result in a low angle grain boundary (low energy, less grain boundary precipitation) and act as heterogeneous precipitation sites that reduce/ remove precipitation at the grain boundary. The precipitation-free grain boundaries resulted in corrosion potentials similar to those of the grain nuclei and provided superior corrosion resistance compared to the other samples.

EXAMPLE 5 - Effect of casting method

Aluminum alloy sheets of alloys A1-A4 were prepared as described above in Example 2 and subjected to homogenization at 560°C, followed by aging for 6 hours, except for differences in the casting method. The samples were prepared in the T6 temper. Different casting methods were used for the different samples, as indicated in FIG. 5: (a) a standard 6xxx series aluminum alloy (A1) cast by continuous casting using a double belt caster ("A1_CC"); (b) A2 cast by continuous caster using a double belt caster ("A2_CC"); (c) A3 cast by continuous caster using a double belt caster ("A3_CC"); (d) A4 cast by continuous casting using a double belt caster ("A4_CC") and (e) A1 cast by direct chill casting ("A1_dC"). FIG. 5 shows optical micrographs of the five samples after being subjected to the corrosion test set forth in ISO 11846B (1995), with an exposure time of 24 hours.

Sample A4_CC showed almost no corrosion pitting compared to the other samples (A1_CC, A2_CC, A3_CC and A1_DC). Samples A1_CC and A1_DC, which had similar compositions, showed different corrosion morphologies due to their different casting and processing methods. The CC process route allowed most of the solute in solid solution to be evenly distributed compared to the dC process route, where the process resulted in microsegregation from grain boundary to grain core which deteriorated the performance/corrosion resistance. Reducing Cu content (A2_CC) also improved corrosion resistance compared to A1_CC, as it reduced total strengthening precipitates which reduced the overall driving force. The reduction of the Si content (A3_CC) also improved the corrosion resistance compared to A1_CC for the same reason. However, Si has a higher diffusivity compared to Cu and therefore the low Si version (A3_CC) showed more corrosion resistance compared to the low Cu version (A2_CC). Finally, the Zr-containing version (A4_CC) showed superior corrosion resistance/performance compared to A1_CC, A2_CC and A3_CC due to higher number density of Zr dispersoids that formed low angle grain boundaries (low energy, less precipitation) and acted as heterogeneous nucleation sites to prevent grain boundary precipitation and improve corrosion resistance. Illustration of Alloys, Products and Methods Not in Accordance with the Present Invention

As used below, any reference to a series of illustrative alloys, products, or methods is to be understood as referring to each of those alloys, products, or methods disjunctively (for example, "Figures 1-4" refer to are to be understood as "Illustration 1, 2, 3 or 4").

Illustration 1 is an aluminum alloy, comprising: 0.2 to 1.5 weight percent Si; (b) 0.4 to 1.6 weight percent Mg; (c) 0.2 to 1.5 weight percent Cu; (d) not more than 0.5 weight percent Fe; (e) one or more additional alloying elements selected from the group consisting of: (e1) 0.08 to 0.20 weight percent Cr; (e2) 0.02 to 0.20 weight percent Zr; (e3) 0.25 to 1.0 weight percent Mn; and (e4) from 0.01 to 0.20 weight percent of V; and (f) with the rest of aluminum.

Illustration 2 is an alloy of any earlier or later illustration, comprising 0.08 to 0.20 weight percent Cr.

Illustration 3 is an alloy of any preceding or succeeding illustration, comprising: not more than 0.02 weight percent Zr; not more than 0.25 weight percent Mn and not more than 0.02 weight percent V.

Illustration 4 is an alloy of any earlier or later illustration, comprising 0.02 to 0.20 weight percent Zr.

Illustration 5 is an alloy of any preceding or succeeding illustration, comprising: not more than 0.10 weight percent Cr; not more than 0.25 weight percent Mn; and no more than 0.02 weight percent V. Illustration 6 is an alloy of any preceding or subsequent illustration, comprising 0.25 to 1.0 weight percent Mn.

Illustration 7 is an alloy of any preceding or succeeding illustration, comprising: not more than 0.10 weight percent Cr; not more than 0.02 weight percent Zr; and not more than 0.02 weight percent V. Illustration 8 is an alloy of any preceding or subsequent illustration, comprising 0.01 to 0.20 weight percent V.

Illustration 9 is an alloy of any preceding or succeeding illustration, comprising: not more than 0.10 weight percent Cr; not more than 0.02 weight percent Zr; and not more than 0.25 weight percent Mn.

Illustration 10 is an alloy of any preceding or succeeding illustration, wherein the aluminum alloy comprises not more than 0.20 weight percent Sr, not more than 0.20 weight percent Hf, not more than 0 0.20 weight percent Er or not more than 0.20 weight percent Sc.

Illustration 11 is an alloy product comprising the aluminum alloy of any previous or subsequent illustration.

Illustration 12 is an alloy product of any illustration 11, wherein the aluminum alloy product is a rolled aluminum alloy product comprising a rolled surface.

Fig. 13 is an alloy product of any of Figs. 11-12, wherein the aluminum alloy product is an aluminum alloy sheet having a thickness of not more than 7 mm.

Figure 14 is an alloy product of Figure 13, where, when subjected to the test conditions set forth in ISO 11846B (1995) over a 24-hour exposure period, the rolled surface has a pitting depth maximum no greater than 140 pm.

Figure 15 is an alloy product of any of Figures 13-14, where the rolled surface has a maximum pit depth no greater than its average grain size, where the average grain size is measured by the method of ASTM E112 (2004).

Figure 16 is an alloy product of any of Figures 13-15, which, when rolled to a thickness of 2 mm and prepared with a T6 temper, has a yield strength of at least 260 MPa, when measured from according to ASTM Test No. B557 (2015), and a bending angle of at least 55°, when measured according to Test No. 238-100 of the German Association of the Automotive Industry ( VDA), with the exception that the test was performed without prestressing.

Figure 17 is a method of making an aluminum alloy product, comprising: providing an aluminum alloy of any of Figures 1-10, wherein the aluminum alloy is provided in a molten state as a molten aluminum alloy ; and continuously casting or chill casting the molten aluminum alloy to form an aluminum alloy product.

Figure 18 is a method of Figure 17, further comprising homogenizing the aluminum alloy product to form a homogenized aluminum alloy product, wherein the homogenization is carried out at a maximum temperature of at least 540° c.

Figure 19 is a method of Figure 17, further comprising hot rolling the homogenized aluminum alloy product to form an aluminum alloy sheet having a first thickness of not more than 7 mm.

Illustration 20 is a method of any of illustrations 17-19, where the aluminum alloy product is formed without using cold rolling.

The invention is defined in the following claims.

Claims (7)

1. An aluminum alloy, comprising: (a) 0.4 to 0.7 weight percent Si; (b) 0.4 to 1.6 weight percent Mg; (c) 0.2 to 1.5 weight percent Cu; (d) not more than 0.5 weight percent Fe; (e) not more than 0.1 weight percent Cr; (f) not more than 0.25 weight percent Mn; (g) not more than 0.05 weight percent of V; (h) 0.02 to 0.2 weight percent Zr; (i) up to 0.1 weight percent Ti; (j) not more than 0.2 weight percent Sn, not more than 0.2 weight percent Zn, not more than 0.2 weight percent Ni, and not more than 0.2 weight percent by weight of Sc, with not more than 0.5 weight percent total; (k) impurities in amounts of 0.05 weight percent or less, where the sum of all impurities does not exceed 0.15 weight percent, with the remainder being aluminum in an amount of at least 95, 0 percent by weight. 2. An aluminum alloy product comprising an aluminum alloy of claim 1. 3. The aluminum alloy product of claim 2, wherein the aluminum alloy product is a rolled aluminum alloy product comprising a rolled surface and/or wherein the aluminum alloy product is an alloy sheet aluminum having a thickness not greater than 7 mm. 4. The aluminum alloy product of claim 3, wherein, when subjected to the test conditions set forth in ISO 11846B (1995) for an exposure period of 24 hours, the rolled surface has a pitting depth maximum pitting depth not greater than 140 |jm and, in particular, where the rolled surface has a maximum pitting depth not greater than its average grain size, where the average grain size is measured by the method of ASTM E112 (2004 ). 5. The aluminum alloy product of claim 3, which, when rolled to a thickness of 2 mm and prepared with a T6 temper, has a yield strength of at least 260 MPa, when measured in accordance with Test of ASTM No. B557 (2015), and a bending angle of at least 55°, when measured in accordance with VDA Test No. 238-100. German acronym Verband der Automobilindustrie), with the exception that the test was performed without pre-stress. 6. A method of making an aluminum alloy product, comprising: providing an aluminum alloy of claim 1, wherein the aluminum alloy is provided in a molten state as a molten aluminum alloy; Y continuously casting or direct cooling casting the molten aluminum alloy to form an aluminum alloy product. 7. The method of claim 6, further comprising homogenizing the aluminum alloy product to form a homogenized aluminum alloy product, wherein the homogenization is carried out at a maximum temperature of at least 540 °C, and/ or further comprising hot rolling the homogenized aluminum alloy product to form an aluminum alloy sheet having a first thickness of not more than 7mm and/or wherein the aluminum alloy product is formed without using hot rolling cold.